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Environmental Science > Renewables And Their Sustainability > Flashcards

Renewables And Their Sustainability Flashcards

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1
Q

What lead to a reduction in the use of renewables?

A

Discovery of fossil fuels

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2
Q

Why did fossil fuels replace renewables?

A

As they were plentiful
Cheap to extract
Very energy dense

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3
Q

What has started a resurgence of renewables?

A

As the impacts of fossil fuels and realisation of how finite they are

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4
Q

Who invented the Diesel engine and when?

A

Karl diesel 1897

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5
Q

What was the car engine originally designed to run off?

A

Peanut oil a renewable

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6
Q

What are biofuels?

A

Liquids derived from plant and animal matter

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7
Q

What are the two main types of biofuel?

A

Bio-ethanol
Bio-diesel

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8
Q

What is bio-ethanol?

A

An alcohol which is made by fermenting the sugar ad starch components of plant materials

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9
Q

What is bio-diesel?

A

Form of diesel form plants or animals
Made by reacting lipids (animal fat, soybean oil) or some vegetable oil with an alcohol

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10
Q

Why is it an advantage of biofuels to have a range of sources/

A

Unlike fossil fuels which are from limited resources
Biofuels can be made from many materials

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11
Q

What are some animal materials that biofuels can be made from?

A

Crop waste
Manure
Other by-products

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12
Q

Why are biofuels renewable?

A

They can be grown again and again to match our needs

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13
Q

How will biofuels increase energy security?

A

Biofuels can be produced locally decreasing dependency on foreign energy (safe of influence)

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14
Q

How do biofuels cause economic stimulation?

A

Produced locally
Manufacturing plants hire local workers
Creating new jobs in rural areas

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15
Q

What are emissions like form biofuels?

A

Less carbon emissions
Produce less carbon and toxins when burned
Some are ‘carbon neutral’

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16
Q

What are the disadvantages of biofuels?

A

Energy output
Hefty carbon emissions (setup)
Affect food prices
Water use

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17
Q

What are he advantages of biofuels?

A

Range of source material
Renewability
Security
Economic stimulation
Lower carbon emissions

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18
Q

How is energy output a disadvantage of biofuels?

A

Lower energy output than fossil fuels so greater quantities needed for same amount of energy

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19
Q

Why is the process to produce the biofuels a disadvantage?

A

The machinery to cultivate the crops and the plants to produce fuel have hefty carbon emissions
Take some time to grow
Increase price of staple foods- tortilla riots
High water use

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20
Q

How do biofuels affect food prices? (Disadvantage)

A

As demand for food crop like corn grows for biofuel production it could cause the price of other staple food crop to increase(tortilla riots)

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21
Q

Why is the water use a disadvantage of biofuels?

A

Massive quantities needed for irrigation of crop and manufacturing the fuel which could affect local and regional water resources

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22
Q

What are some examples of biofuels being researched/ produced?

A

Sugar cane
Maize corn
Jatropha
Waste (poo bus)
Algae
Switch grass

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23
Q

What were the tortilla riots?

A

tens of thousands of people protested in Mexico City against the soaring prices of tortillas, from US$ 5.00 the year before to up to US$ 20.00 in some regions,
As it was an essential part of the Mexican diet and culture

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24
Q

What is the poo bus?

A

This was an initiative to power a bus by using bio methane form treated waste

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25
Q

How can algae by used as a biofuel?

A

carbohydrates (sugars) from algae can be fermented to make additional biofuels, including ethanol, as well as other products such as plastics and biochemicals.

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26
Q

Why is switch grass being considered as a biofuel?

A

yields more than 540 percent more energy than the energy needed to produce and convert it to ethanol

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27
Q

Why does solar power technology need to be improved?

A

As their is enough solar energy at any one point for all human needs however the storage tech and solar panel tech is inefficient

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28
Q

What are the different ‘types’ of solar power?

A

Photothermal solar power
Solar power heat pumps
Photovoltaic solar power
multi-junction photovoltaic cells
Anti-reflective surfaces
CSP- concentrating solar power

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29
Q

What is photo-thermal solar power?

A

Suns energy absorbed in order to produce heat
Usually used to heat water (could be used for space heating, homes)
Heated water stored in an insulated tank for some hours then used later

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30
Q

What are solar heat pumps?

A

Pumps that take heat from the earth and into a home (expensive)
Uk government will fund half the cost
Solar panels can be used to to produce energy needed for the pump

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31
Q

What is the problem with solar heat pumps?

A

The PV panels produce little electricity in winter when you need the heating the most

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32
Q

What is photovoltaic solar power? (With advantage and disadvantage)

A

PV- used to create electricity
Photovoltaics is turning light into electricity (solar power calculators)
Advantage- long lifespan of 40+ years
Disadvantage- not very efficient at conversion

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33
Q

What are multi-junction photovoltaic cells?

A

Cell produces electric current in response to different wave lengths of light
Use of multiple semiconducting materials allows more wavelengths of light to be absorbed improving efficiency
Normal PV cells are 33% efficient and under normal conditions Multi-junction cells are 46% efficient

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34
Q

What are anti-reflective surfaces?

A

The shiny surface of solar panels causes it to reflect light (up to 30%)
Using a grooved/ textured surface reduces reflectivity so more light can be absorbed

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35
Q

How can biomimetics be used for anti-reflective surfaces?

A

By mimicking the structure of the cornea of a moths eye as they are excellent at absorbing light

36
Q

What is CSP? (Solar)

A

Concentrating solar power plants uses mirrors to concentrate the suns energy to drive steam turbines to produce energy
Thermal energy from a CSP plant can be stored for when its needed (day or night) reducing intermittency

37
Q

What is HEP, Hydro electric power?

A

Electricity from the kinetic (movement)energy produced when water drops or flows downhill

38
Q

What must be present of HEP to be really viable?

A

A good volume of water (frequent rainfall)
Good gradient drop (head)
Low water turbidity
Low seismic activity
Impermeable bedrock

39
Q

What are the two main types of HEP?

A

Low head turbines
Helical turbines

40
Q

What are low head turbines?

A

Used in rivers with a head of 20 metres or less to produce energy
The head can either occur naturally (waterfall) or is produced by constructing a dam in a river creating a reservoir
Controlled release of water from the reservoir drives a turbine very effective but has drawbacks

41
Q

What are the benefits of low head HEP?

A

Medium efficiency
No need for invasive infrastructure- no huge reservoir/ land flooding
Low operational costs
Long lifetime
Low pressure differences and low rpm wont harm or kill migrating fish and machinery is partly or fully above water

42
Q

Where can low head HEP be used?

A

Can be priced for rivers and estuaries
Weirs, streams, locks, rivers and wastewater outfalls

43
Q

Are there any problems with low head HEP?

A

A large volume of water is required to generate significant power using conventional technologies

44
Q

How can the efficiency of HEP be improved?

A

Using helical turbines

45
Q

What are the benefits of helical turbines?

A

Turbid water can be used (grey water)
They don’t harm fish
Water channels can be slower and smaller

46
Q

What is wind?

A

Where air masses move from areas of high pressure to low pressure in order to try equalise pressure differences

47
Q

What is the actual name for wind turbines?

A

Aero generators

48
Q

What does HAWT stand for?

A

Horizontal axis wind turbines

49
Q

Why is HAWT used?

A

Its been around for so long the technology is established and is more efficient

50
Q

What are the issue with HAWT?

A

Need very tall towers to prevent blades reaching the ground
Tower has to be bigger to support generator
Blades are so long that they can be prone to cracking due the forces they are put under

51
Q

What are the advantages of HAWT?

A

Very efficient
High power output
High operational wind speed

52
Q

What are the disadvantage of HAWT?

A

Difficult to transport, setup and maintain
Negative environmental impact
Eyesore

53
Q

What is VAWT?

A

Vertical axis wind turbine

54
Q

What are the advantages of VAWT?

A

Produces energy at a very low wind speed
Slower blade speed as blades are closer to axis of rotation

55
Q

What are the disadvantage of VAWT?

A

Not as efficient as HAWT

56
Q

What is wind assisted propulsion?

A

Practice of decreasing the fuel consumption of a merchant vessel through the use of sails or some other wind capture device

57
Q

What vehicle is being used for wind assisted propulsion?

A

Ships by converting kinetic energy to thrust

58
Q

What are the three ideas for wind assisted ships?

A

Wing sail concept
Kite sail
Flettner rotor

59
Q

What is the idea of wind power ships?

A

Not to be the main source of power but support Diesel engines and reduce emissions and fuel
14% drop in fuel use

60
Q

What makes an area viable as a wind farm?

A

Frequent and reasonably high velocity winds (not too high)

61
Q

What locations are wind farms generally located?

A

Coastal locations
Flat locations
In the sea
Upland

62
Q

What are the common issues with wind farms?

A

May be in picturesque location so might affect beauty
Ecological impacts could threaten birds and bats (male bats)
Set up requires large machinery which could damage habitats

63
Q

How is wave power produced?

A

The up and down motion of floating devices placed on the ocean surface

64
Q

What are the positives of wave power?

A

Free
Sustainable
Renewable
Produces zero waste

65
Q

When was the first commercial wave energy system used?

A

Scotlands islay in 2000

66
Q

What is the most common type of wave power technology?

A

Uses buoys or floats systems that rely on the rise and fall of swells to drive hydraulic pumps

67
Q

What are the disadvantages of wave energy?

A

High production and installation costs
Complicated maintenance and repair logistics
Potential threats to marine life
Noise pollution of onshore and off shore structures

68
Q

What is geothermal energy?

A

Heat that comes from the sub-surface of the earth
It is contained in the rocks and fluids beneath the earths crust

69
Q

How is geothermal energy produced?

A

Well are dug a mile deep into underground reservoirs to access the steam and hot water which can be used to drive turbines connected to electricity generators

70
Q

What is geothermal district heating? (GeoDH)

A

The use of geothermal energy to heat individual and commercial buildings

71
Q

What are the positives of geothermal?

A
  • environmentally friendly without significant amounts of pollution
  • geothermal reservoirs and naturally replenished thus renewable
  • massive potential, 2 Terawatts
  • excellent for meeting base load energy demand
  • no fuels needed for extraction less fluctuations of cost and electricity costs
  • small footprint on the land, partially underground
  • recent tech advancements, resources more exploitable and lowered costs
72
Q

Negatives of geothermal?

A

Minor environmental issues- water wastes can contain salt and heavy metals and some gases (hydrogen sulphide)
In extreme cases the plants can trigger earthquakes
Heavy upfront costs
Very location specific need to be at least 150*c so volcanically active or drill deep (expensive)

73
Q

What is a new geothermal technology?

A

Low temperature fluids

74
Q

What are low temperature fluids? (geothermal)

A

New turbine technologies that are being developed that use cooler liquids meaning water as cool as 60*c can be sued to boil butane or pentane

75
Q

What does low temperature fluids mean for the uk? (Geothermal)

A

Cooler rocks could be sued like those in Cornwall

76
Q

How are tides formed?

A

The gravitational attraction between the earth and the moon

77
Q

How many ‘tides’ are there in a day?

A

2 high and 2 low tides every 25 hours

78
Q

What are the three types of power/location that can be harnessed? (TIDAL)

A

Tidal barrage
Tidal lagoon
In stream turbines

79
Q

What is a tidal barrage?

A

Where turbines are set across an estuary
Tides are predictable
Narrow area ensures all flow travels over turbines meaning good energy production

80
Q

What are the negatives of tidal barrages?

A

Expensive and has environmental costs
Considerable construction so impacts of material extraction and the barrage can affect hr heights of tides
Can increase pollution build up around them due to settlement of sediments

81
Q

What is a tidal lagoon?

A

Same as a tidal barrage but smaller
A small area of coastline in enclosed
Impacts are the same but smaller
Migratory fish are able to pass causing less harm to the food chain

82
Q

Who built the largest tidal lagoon in 2011?

A

South Korea

83
Q

What is an example of a tidal lagoon in the uk?

A

Plan to build one in Swansea
The walls will capture water when tide comes in and hold it when it goes out
The walls will release the water back into the sea turning turbines making electricity
Will power 155000 homes

84
Q

What are in-stream turbines?

A

Function like underwater wind turbines
Also called tidal turbines
Cheapest and least ecologically damaging
Potential power generation greater than wind turbine

85
Q

Why are water turbines better than wind turbines?

A

Water is 800x denser than air so more power at low tidal flow velocities with similar wind speeds

Environmental Science (90 decks)

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